The statements in this section merely provide background information related to the present disclosure and can not constitute prior art.
An axial turbomachine compressor usually has an external housing to which rows of vanes are attached. They can be attached in grooves, or using fitting bolts passing through the wall of the housing. This solution is particularly advantageous if the wall is essentially thin, measuring a few millimeters. Each vane then has an attachment platform with one surface in contact with the internal surface of the wall of the housing.
For reasons of mechanical strength, the vanes and the platforms can be made of metal, for example steel or titanium alloy. The wall is made of a composite material in order to lighten the housing. For optimum mass saving, the composite can include a polymer resin combined with reinforcement incorporating carbon fibers.
Document EP 2 402 615 A1 discloses an axial compressor with an external housing made of a composite material. The wall of same has three annular rows of vanes that are pressed flat at the platforms of same. The mechanical connection is provided by attachment elements. This teaching tends to optimize the rigidity and lightening of the stator. However, during assembly, stresses are concentrated at the interface between the wall and the platforms, potentially resulting in damage caused by differences in hardness. It is taught here to add joints for absorbing shocks at the interface between the wall and the platforms in the event of ingestion. However, the elasticity of the joints reduces rigidity, and the addition of same increases mass. This solution complicates assembly.
This teaching optimizes the strength of the composite housing. However, the rigidity of same remains low, and can become insufficient in the case of external compressor housings since such housings are subject to high stresses. In the event of loss of a fan vane, the turbomachine undergoes high-amplitude vibration, and the housing is then highly stressed. Thermal stresses and humidity also significantly reduce the mechanical strength of the housing.